The latest snapshots show the pregnant royal wading through the surf in a blue Vix bikini, her barely-there baby bump on full display for the first time. (Until now, Middleton has kept a relatively low profile. Earlier this month, she stepped out in London but kept her growing belly mostly hidden in a wool, tartan-plaid cape from Zara.)

Speaking about the bikini bump pictures, which will hit stands on Feb. 13, St. James's Palace said in a statement that they were "disappointed that photographs of the Duke and Duchess on a private holiday look likely to be published overseas. This is a clear breach of the couple's right to privacy."

Indeed, a source tells Us Weekly that the royal parents-to-be are disheartened by the unauthorized photos. "It's been a real sour note for the end of their trip," the insider says. "For Catherine, it was the first time she had shown her baby bump, and so for it to be exposed so quickly has shaken her up a little. They thought with the privacy laws on the island they would be able to spend a moment outside of the house without this happening."

No word yet on whether St. James's Palace plans to take legal action over the publication of the intimate snapshots.